Fractionation of alfalfa wetted with molasses serum

ABSTRACT

A process for fractionating leafy green crops is disclosed. This process involves the separation of at least one valuable constitutent from the crop and preferably comprises the production of a dehydrated green crop together with one or more valuable by-products. The process includes a pressing or squeezing of the green crop which has been mixed with molasses serum which is a by-product of the operation. The pressed crop may then be dehydrated by normal methods. The rolled juice which is expelled from the wetted squeezed crop is then treated to coagulate a valuable protein therefrom and the remaining liquid is a molasses serum which is recycled to the green crop prior to the pressing step. That portion of the molasses serum which is not required for mixing with the green crop may be added to the pressed cake. Specific process steps regarding the process as applied to alfalfa are also disclosed.

United, States Patent [191 Batley, Jr.

[ NOV. 27, 1973 FRACTIONATION OF ALFALFA WETTED WITH MOLASSES SERUM [76]Inventor: William R. Batley, Jr., PO. Box

216, Brawley, Calif. 92227 [22] Filed: Aug. 2, 1971 i [21] Appl. No.:167,901

[52] US. Cl 426/378, 260/112, 426/489,

' 426/454 [51] Int. Cl A23k 1/02 [58] Field of Search 99/6, 17, 8, 14,

[56] References Cited UNITED STATES PATENTS 3,551,163 12/1970 Vincent99/6 1,996,395 4/1935 Arnold 99/6 2,552,343 5/1951 Peebles ..'99/83,637,396 1/1971 Hollo 260/112 3,684,520 8/1972 Bickoff 99/8 1,201,66310/1916 Werner 99/8 1,816,998 8/1931 Cushman 99/8 2,021,996 11/1935l-langlein 99/8 2,504,159 4/1950 Singer 99/8 2,940,857 6/1960 Andrews99/8 OTHER PUBLICATIONS J. Agr. Food Chem., Vo1. 18, No. 6, P10864089,

1970 Knuckles. Isolation of Leaf Components-Chayen J. Sci. Food Agric.,1961, PS02-512.

Primary Examiner-Norman Yudkoff Assistant Examiner-Hiram H. BernsteinAttorney-Lyon & Lyon 5 7] ABSTRACT A process for fractionating leafygreen crops is disclosed. This process involves the separation of atleast one valuable constitutent from the crop and preferably comprisesthe production of a dehydrated green crop together with one or morevaluable by-products. The process includes a pressing or squeezing ofthe green crop which has been mixed with molasses serum which is aby-product of the operation. The pressed the pressing step. That portionof the molasses serum which is not required for mixing with the greencrop may be added to the pressed cake. Specific process steps regardingthe process as applied to alfalfa are also disclosed.

12 Claims, 1 Drawing Figure /0 FRESH cur CHOPPER ALFALFA MIXER I ,ea

suePLus S RU 23 COOLED ROLL PRESS PRESSED l/ HOR'ZONTAL DEHYDEATEDMOLASSES CAKE ROTARY ALFALFA srseuM DRUM DElEQ ROLLED AMMONIA Jule-E /7-STEAM HEATER /&

COOLER 2/ 20) DRIED SEPAEATOR CURB DR PROTEIN cueo MOLASSES SERUMFRACTIONATION F ALFALFA WETTED WITH MOLASSES SERUM BACKGROUND OF THEINVENTION The field of the invention is the processing of green cropsfor use in animal, poultry or human feed. The dehydration of green cropssuch as alfalfa has been carried out for many years and typicallyutilize the steps of choping the crop into relatively small pieces,passing it through a dehydrator such as a rotating gas-fired horizontal.drum dryer to produce a dehydrated product. This process has becomeparticularly refined for use with alfalfa and the quality of theresulting dehydrated alfalfa ,(herein dehy) has been substantiallyimproved by such steps as storing the product in a nonoxidizingatmosphere, the addition of chemical antioxidants, pelletizing, cubing,and air-classifying. These improvements have helped reduce processingcosts as well as increase the quality of the resulting dehy.

In spite of the manyimprovements which have been introduced, there areseveral significant factors which have limited the use of dehy. First,the use of dehy in poultry feed has been limited by the relatively highfiber content of normal dehy.Secondly, the capacity of the commonly usedrotary dryer is limited by the relatively high moisture content of thechopped green alfalfa thereby adversely affecting the cost of thedehydrating process. It has recently been discovered that a proteinconcentrate can be produced by the coagulation of juice which has beensqueezed from fresh green crops. This pressing step further increasedthe production of the dryer in that it reduces the amount of moisturewhich must be driven from the crop. Because of the relatively fiberousnature of green crops and the high production volumes, most means ofsqueezing have not proved economically justified. It has been foundhowever that the use of sugar cane rolls can remove some juice fromgreen crops and a process utilizing such equipment is disclosed in thefollowing articles: Alfalfa Products By Wet Fractionation by R.R.Spencer et al, Transactions of the ASAE, Vol. 13, No. 2, pp. 198-200,1970; PRO-XAN Process: Incorporaa tion and Evaluation of Sugar CaneRolls in Wet Fractionation of Alfalfa, B.E. Knuckles et al, J Agr. FoodChem. Vol. 18, No. 6, pp. 1086-89; and Big Squeeze: Getting The Most OutOf Alfalfa, Agr. Research, US.- D.A., September I969 pp. 6-7 and thesearticles are incorporated by reference herein to illuminate thebackground of the present invention.

Briefly, the wet fractionation of green crops includes the steps ofpassing the green crop through sugar cane rolls to produce a relativelydry pressed cake and a liquid referred to as rolled juice. The pressedcake is dried in the normal manner to provide a dehydrated feed which,in the case of alfalfa, is a widely used commercial product. The rolledjuice is coagulated by means such as heating which results in a curd anda liquid referred to as molasses serum. The curd is dried to form afiber-free protein concentrate which has been found to be a valuablepoultry feed additive and is further of great interest as a food forhumans. The product is a free-flowing, fiber-free powder or granule.

This process, although widely practiced on a pilot plant scale by theUnited States Department of Agriculture has been found difficult tocarry out on the full scale commercial basis. This difficulty resultsfrom an inability to remove a sufficient amount of protein from thegreen crop during the sqeezing operation so that the increased value ofthe protein does justify the cost of the equipment required to recoverit. When the sugar cane rolls are adjusted to increase the amount ofliquid expelled, the rolls must be so close together that the green cropwill not pass through them but instead will build up on the upstreamedge of the nip of the rolls. Conversely, when the sugar cane rolls areopened enough to provide the desired output of pressed cake, thepressure is not sufficient to expel an economically useful amount ofrolled juice. Thus, in practice, it was found that the desired processdescribed above and in the articles incorporated by reference herein wasnot practical on a large scale commercial basis.

SUMMARY OF THE INVENTION It has been discovered that the output of driedprotein from the wet fractionation of leafy green crops may be greatlyincreased by feeding a stream of molasses serum to the green crops priorto the squeezing operation. The molasses serum is the liquid by-productrecovered when the dried protein curd has been removed from the rolledjuice produced by the squeezing operation. Thus, in effect, a closedloop is provided whereby a molasses serum is circulated into the greencrop prior to squeezing, is held for a short time in intimate contactwith the crop thereby dissolving protein from the crop, is next squeezedand removed from the crop together with its dissolved protein, is'passed' through a coagulation step wherein the protein is separated andthen is returned to the cycle to be again mixed with the leafy greencrop. The commercial practice of this process has been found to increasedried protein yield over 300 percent. Any excess of molasses serum whichis developed over that needed for the dissolving cycle may be added tothe pressed cake prior to or during the drying thereof.

BRIEF DESCRIPTION OF THE DRAWINGS The drawing shows a flow sheet of theprocess of the present invention as applied to alfalfa.

DESCRIPTION OF THE PREFERRED EMBODIMENTS By way of example, the processof the present invention will be described with reference to the leafygreen crop alfalfa. It is to be understood, however, that the processmay be applied to other crops with the modifications in operatingconditions dictated by differences in the particular crop. Referring tothe drawings, fresh cut alfalfa 10 is fed to a conventional chopperwhich serves to cut up the alfalfa into a desired size and produces whatis commonly called green chop. A stream of cold (below F) molasses serum12 is added to chopper 11 which thereby serves both a chopping andmixing function. This green chop and serum mixture is next fed to a rollpress 13 which comprises a commercially available sugar cane roll press.This utilizes three rolls which is driven by an electric motor through areduction gear. The press should be operated with a roll spacing suchthat the alfalfa will not be held upstream of the nip of the rolls. Aslong as the delay has the required amount of protein, the nip should beadjusted as small as possible to maximize the amount of rolled juiceproduced. The pressed cake from the roll press is fed through aconventional dryer 15 to produce dehydrated alfalfa with a proteincontent of l7 percent or greater.

The rolled juice 16 is pumped from roll press 13 and its pH is adjustedto between 8 and 9 by feeding a stream of ammonia 17 into the juice. Apreferable pH is 8- /2. The juice is next heated by the injection ofsteam 18 in a heater 19 to increase its temperature to 180 F.

The heated rolled juice is next fed to a separator 20 where the proteincurd is permitted to rise to the top and the molasses serum is drawnfrom the bottom. By feeding an inert gas such as nitrogen into theseparator, this separation may be improved. Also, by permitting a longperiod of standing, the curd will settle and may be separated by anymeans such as filtration or centrifugation. The curd is next passed to adrum type dryer 21. Other means of drying such as spray drying may alsobe used. This dryer produces the dried protein curd which has found wideacceptance as a high energy feed additive.

The molasses serum which still contains some ammonia, is next cooled incooler 22 which may be an evaporative cooler. It is preferable that theserum be cooled to below about 100 F so that no protein will becoagulated in the chopper-mixer 11 or in the roll press 13. Any molassesserum which is not required to sufficiently wet the alfalfa ispreferably passed through line 23 and combined with the pressed cakefrom roll press 13. It is standard practice to feed some water to agasfired rotary alfalfa dryer when the dryer begins to produce an excessof smoke. This smoke is believed caused by the burning of a portion ofthe crop and the addition of water tends to reduce the burning. Theserum not only performs this function but also provides additional feedvalue and solids content to the resulting dehy in that the serumcontains dissolved sugar and other beneficial ingredients.Alternatively, this excess serum may be collected and sold in its liquidform since it is a source of soluble vitamins and UGF (unidentifiedgrowth factors) useful in poultry feed.

The providing of a closed loop of molasses serum causes a surprising andsubstantial efiect on the fractionating process. The followingcomparison shows a typical material balance with and without the closedloop serum stream. The input in both instances is 45 tons per hour ofgreen chop which is continued for 24 hours a day. This input producedthe following over a 24 hour period:

WITH RECYCLE Dehy 216 tons Dried Protein Curd 10 tons An economiccomparison at present day values (dehy $50 per ton and dried proteincurd $l40 per ton) is as follows:

WITHOUT RECYCLE Dehy 223 tons Dried Protein Curd 3 tons WITH RECYCLEDehy value $10,800

Dried protein curd value 420 value 1,400 TOTAL $11,570 TOTAL $|2,200

WITHOUT RECYCLE Dehy value $1 l,l50 Dried protein curd tein content isnot necessarily beneficial. There is a growing need for long fiberroughage in dense form for dairy and beef cattle. Protein content isbecoming of less importance in cattle feed because of the use of lowcost urea and other non-protein nitrogen (NPN) products in place ofprotein. Thus, the practice of the present invention does not detractfrom the market value of the resulting dehy. It has furthermore beenfound that the removal of juice from the alfalfa prior to the pressedcake dryer permits a lower retention time of the pressed cake in thedryer which in turn leads to reduced burning losses in the dryer.

An earlier attempt was made to increase protein yield by adding water tothe chopper-mixer much the same way that the molasses serum is added. Itwas found however that the water only slightly increased the proteinyield and did not approach the increase found by the addition ofmolasses serum. The amount of molasses serum which is surplus has beenfound to be a relatively small amount and often no sur-plus at allresults. The feeding of this surplus serum to the dryer eliminates adisposal problem as well as increasing the amount of solids from thedryer.

Other examples of green crops useful with the present invention includegrasses, clover, and leafy green vegetables such as lettuce, pea or beanvines, celery or beet tops, barley, and sorghum. The amount of molassesserum which is recycled is such that the green chop is completely wettedby the serum. An excess of serum is not detrimental in that it merely isexpelled with the rolled juice and thus does not substantially add tothe process and cost. It is necessary that the serum be added to thegreen chop prior to the pressing or squeezing step so that it will beforced into the cells of the alfalfa as it is squeezed and thus becapable of dissolving a significant amount of protein from the alfalfa.The effect is thus both a physical washing off and also a sponge effectwhere the serum enters the cells of the alfalfa and is squeezed out bythe sugar rolls.

Another area of recent interest is the use of alfalfa as a source offood for humans. It has long been known that alfalfa produces moreprotein per acre than any other cultivated crop but due to its higherfiber content has not been believed to be adaptable for human food. Thedried protein curd does not have this shortcoming and can be utilized byhumans since it does not contain any fibers. The dried protein curd isalso high in xanthophyll which makes it particularly useful as a pigmentation supplement for poultry feed.

The present embodiments of this invention are to be considered in allrespects as illustrative and not restrictive, the scope of the inventionbeing indicated by the appended claims rather than by the foregoingdescription, and all changes which come within the meaning and range ofequivalence of the claims therefore are intended to be embraced therein.

What is claimed is:

l. A process for dehydrating green leafy plants comprising:

mixing said plants with a recycle molasses serum to produce a wettedplant feed;

passing said wetted plant feed through a press to expel a portion of thejuice from said feed, thereby producing a pressed cake and a rolledjuice stream; coagulating said rolled juice stream to form a curd;separating said curd from the uncoagulated portion of said rolled juicethereby producing a protein curd portion and a molasses serum portionwhich provides the source of said recycle molasses serum, and

passing said pressed cake through dehydrating means to drive offmoisture therefrom.

2. The process of claim 1 wherein any excess portion of said recyclemolasses serum is added to said pressed cake.

3. The process of claim 1 wherein said coagulating step is carried outby heating said rolled juice to a temperature at which a protein curd isformed therein.

4. The process of claim 3 wherein said recycle molasses serum is cooledto a temperature at which no protein contained in said crop iscoagulated before said serum is mixed with said plants.

5. A process for dehydrating freshly cut alfalfa comprising:

mixing said alfalfa with a recycle molasses serum which has been cooledto below about 100 F to produce a wetted alfalfa feed;

passing said wetted alfalfa feed through a press to expel a portion ofthe juice from said feed thereby producing a pressed alfalfa cake and arolled juice steam; heating said rolled juice stream to about 130 F tocoagulate a portion of said rolled juice into a curd;

separating said curd from said rolled juice to provide a wet proteincurd and a molasses serum which serves as a source of said recyclemolasses serum; and

passing said pressed alfalfa cake through dehydrating means to drive offmoisture and produce dehydrated alfalfa.

6. The process of claim 5 wherein ammonia is added to said rolled juicestream to adjust its pH to between about 8 and 9.

7. The process of claim 5 wherein said press is a three roll press.

8. The process of claim 5 wherein a portion of said recycle molassesserum is combined with said pressed cake.

9. In a wet fractionation process for the dehydration of alfalfa of thetype comprising a pressing of the fresh alfalfa to expel liquidtherefrom prior to the dehydration of the resulting pressed cake andfurther wherein the roller juice resulting from the pressing step iscoagulated to form a protein curd and a molasses serum, the improvementwhich comprises:

mixing at least a portion of said separated molasses serum with saidalfalfa prior to the pressing thereof, the amount of said serum beingsufficient to completely wet the alfalfa.

10. The process of claim 9 including the further improvement of addingammonia to said rolled juice.

11. The process of claim 9 including the further improvement of coolingsaid molasses serum to below about F.

12. The process of claim 9 wherein any excess molasses serum is added tosaid pressed cake before it iscompletely dehydrated.

2. The process of claim 1 wherein any excess portion of said recyclemolasses serum is added to said pressed cake.
 3. The process of claim 1wherein said coagulating step is carried out by heating said rolledjuice to a temperature at which a protein curd is formed therein.
 4. Theprocess of claim 3 wherein said recycle molasses serum is cooled to atemperature at which no protein contained in said crop is coagulatedbefore said serum is mixed with said plants.
 5. A process fordehydrating freshly cut alfalfa comprising: mixing said alfalfa with arecycle molasses serum which has been cooled to below about 100* F toproduce a wetted alfalfa feed; passing said wetted alfalfa feed througha press to expel a portion of the juice from said feed thereby producinga pressed alfalfa cake and a rolled juice steam; heating said rolledjuice stream to about 130* F to coagulate a portion of said rolled juiceinto a curd; separating said curd from said rolled juice to provide awet protein curd and a molasses serum which serves as a source of saidrecycle molasses serum; and passing said pressed alfalfa cake throughdehydrating means to drive off moisture and produce dehydrated alfalfa.6. The process of claim 5 wherein ammonia is added to said rolled juicestream to adjust its pH to between about 8 and
 9. 7. The process ofclaim 5 wherein said press is a three roll press.
 8. The process ofclaim 5 wherein a portion of said recycle molasses serum is combinedwith said pressed cake.
 9. In a wet fractionation process for thedehydration of alfalfa of the type comprising a pressing of the freshalfalfa to expel liquid therefrom prior to the dehydration of theresulting pressed cake and further wherein the roller juice resultingfrom the pressing step is coagulated to form a protein curd and amolasses serum, the improvement which comprises: mixing at least aportion of said separated molasses serum with said alfalfa prior to thepressing thereof, the amount of said serum being sufficient tocompletely wet the alfalfa.
 10. The process of claim 9 including thefurther improvement of adding ammonia to said rolled juice.
 11. Theprocess of claim 9 including the further improvement of cooling saidmolasses serum to below about 100* F.
 12. The process of claim 9 whereinany excess molasses serum is added to said pressed cake before it iscompletely dehydrated.